[fallingfrog]

I can’t get the whole article to load.. but my hot take is, for the most part, in all the places where the conditions are right for trees to grow, there are trees there already. The exceptions are just those places where the trees have been deliberately cleared by humans, to make room for agriculture or grazing animals (as in pre-Columbian America as I suspect the article points out). But allowing all those areas to regrow cant be sufficient: If it were, could you not make the argument that it was the clearing of all those areas in the first place that caused all the warming we’ve seen so far?

[Tepix]

No, trees don't just regrow if you've cut them down on a large scale. The landscape changes permanently.

[fallingfrog]

Well, “permanently” on human lifetime time scales perhaps. I’m just saying you probably can’t get forests to grow in places where they never occurred naturally pre-civilization.

[gshdg]

There are enormous swathes of land that used to be forested that no longer are because we cut or burned trees either to use the lumber or to clear the land for agriculture.

Sure, in tens of thousands of years, trees would likely eventually repopulate that land; but that’s an extremely gradual process, as most trees’ seeds don’t disperse very far, and it takes years for each new tree to mature enough to produce seeds to extend the forest’s reach.

Whereas if we seed those areas directly, we could have forests again within decades.

[fallingfrog]

Ok, that may be true but you're still not really understanding my argument. I'm going to spell it out.

Assume: The land we're reforesting is land that humanity deforested. Hopefully I don't need to make that argument, it should be clear.

Assume: If reforesting land causes cooling, then deforesting the same land caused the same amount of warming.

Let A=the amount of warming you get by deforesting some land, also the amount of cooling you get by reforesting the same land.

Let B=the amount of warming you get from shoving CO2 into the atmosphere.

Let C=the total amount of warming so far.

Then A+B=C

If you're making the argument that A=C, then B=0

But B is not equal to 0.

Therefore A is not equal to C.

That means: reforesting all the land we deforested is not going to cancel out the CO2 we've put into the atmosphere.

Does that help clarify my point? Reforestation BY ITSELF cannot be enough.

[electricviolet]

> Reforestation BY ITSELF cannot be enough.

Of course it's not. That's stated very clearly in the article.